Electromagnetic oscillation apparatus



1940' A. ALLERDING ETAL ELECTROMAGNETIC OSCILLATION APPARATUS Filed Oct. 26, 1937 2 Sheets-Sheet l Dec. 31, 1940. A. ALLERDING ETAL 2,226,653

ELECTROMAGNETIC OSCILLATION APPARATUS Filed Oct. 26', 1957 2 Sheets-Sheet 2 &

l av av Patented Dec. 31, 1940 UNITED STATES ELECTROMAGNETIC OSCILLATION APPARATUS Alfred Allerding, Berlin-Friedrlchshagen, and

Walter Dallenbach, Berlin-Charlottcnburg,

Germany. aasignors to Julius Pintsch Kommandltgesellschaft, Berlin, Germany Application October 26, 1937, Serial No. 171,148 In Germany November 4, 1936 9 Claims.

This invention relates to apparatus for the generation, amplification, or reception, of electromagnetic oscillations, especially ultra-high-frequency oscillations, preferably in'the sphere of 6 metre, decimetre, or centimetre waves by means of electron tubes and frequency-determining resonators.

Such apparatus according to the present invention comprises a dielectric guide composed l partly of a. resonator comprising a chamber having metallically conductive internal surfaces and partly of an electrode of an electron discharge path contained within a portion of the internal space of said chamber that is separated in a 18 vacuum-tight manner from the remainder of the said internal space and is exhausted.

Preferably the exhausted portion of the internal space of the said chamber is contained within a cartridgei. e., an electron tube which 20 is constructed so as to be readily insertable into the chamber of a resonator so as to constitute therewith a. dielectric guide for waves generated in the tube or to be amplified or received by the tube and also so as to be readily removable 25 from the said chamber.

In the accompanying drawings- Figure 1 is a diametral section through a cartridge constructed in accordance with this invention.

30 Figure 2 is a similar view disclosing a second form of such cartridge.

Figure 3 is a view partly in section and partly in elevation and showing the cartridge of Figure 1 enclosed in a resonator.

35 Figure 4 is a view partly in section and partly in elevation and showing the cartridge of Figure 2 used with a resonator.

In the example shown in Figure 3 the external conductor of a concentric dielectric guide con- 40 sists of a metal tube 26 and the internal conductor partly of two tubular parts 21. The tubular parts 21 are split and engage elastically with, so as to make a good electrical contact with, the caps 2 and 32 of an electron tube or 45 cartridge 22 the internal construction of which is shown in Figure .1. As hereinafter stated the caps 2 and 32 are conductively connected together by the rods of the grid and the grid and the caps consequently constitute with the parts 21 the 50 internal conductor of the concentric dielectric uide the external conductor of which is the wall 26 of the chamber of the resonator. The external conductor 26 is coupled capacitively with the metal cylinder 33 of the cartridge and for 55 this purpose there is a sufliciently small distance plate 2 1'.

between the metal cylinder 33 of the cartridge and the metal cylinder 26. Insulating pieces 34 ensure the desired distance apart.

The external conductor 26 is coupled capacitively, and the internal conductor 21 galvanically, 6 with the discharge path. Both of the parts 26 and 21 may be coupled capacitively or galvanically with the discharge path or the internal conductor 21 may be coupled capacitively and the external conductor 26 galvanically with the disl0 charge path. r

The resonator 26, 21 is closed at one end by a This plate is arranged to be removable in order to render possible the easy introduction of the cartridge 22. The plate 2| consists of metal and is galvanically connected with the adjacent edge of the metal tube 26. On the plate 2| there is placed an insulating piece 35 which serves for supporting the terminals 26. The portion of space surrounding the cartridge 22 is preferably under atmospheric pressure.

At the other end of the external conductor 26 there is provided a piston 24 which is adjustable for example by means of a screw-thread and serves for tuning the resonator. The cartridge 25 22 is arranged in a potential loop of the resonator. The concentric dielectric guide 26, 21 oscillates as a x/2 resonator with a potential node at each end, A indicating the length of the resonant wave. The adjustable piston 24 may for example be arranged in the way shown so that it serves at the same time as a medium for transmission between the chamber resonator and a dielectric guide leading to a utilising device. The dielectric guide leading from the resonator has as an internal conductor 23 a prolongation of the tube 21 and as an external conductor the tube 25. The capacity between the internal surface of the piston 24 and the opposite portion of the external surface of the tube 21 is so dimensioned that it tends to produce the desired fixing of the potential node at the load end of the resonator and to prevent undesired radiation.

The cartridge 22 is a high-vacuum electron tube containing a hot cathode 26, a grid I and an anode 1. The cathode 28 is a hair-pin cathode the incandescible wire of which is connected at one end to leading-in wires 30 and 3| and is supported at the other end by a spring 29. The grid I is a squirrel-cage grid formed by rods held at both ends by the annular parts or caps 2 and 32 in which they are welded and which consist of electrically highly conductive material as copper or silver. The spaces between the rods I are. advantageously such as to allow of the passage of the electrons but to prevent the passage of the ultra-short waves so that the space containing the cathode and bounded by the grid is kept free from ultra-short waves. In the widened por tions of the caps there are inserted rings 3 and 4 of ceramic material. The ring 3 is provided with openings through which pass the conductive leads 30 and 3| and the ring 4 is hollow and is crossed by a bar to which one end of the spring 29 is attached. The ceramic ring 4 carries the exhausting tube 5, which consists of metal, and which, after the cartridge has been exhausted of air, is sealed by the glass flux hereinafter mentioned. The tube 5 is enclosed in the tube 21. Over the caps 2 and 32 carrying the grid there are fitted annular disks 6 which are of ceramic material and upon which the edges of the anode 'l are fitted. The ceramic disks 6, are arranged perpendicularly to the axis of the anode I, and consequently to the course of the ultrashort waves; and they secure an accurate centering of the grid within the anode I and serve further in conjunction with the ceramic parts 3 and 4 for making the cartridge tight to high vacuum. The anode I has a middle portion of relatively smaller diameter than the end portions so as to provide between each disk 8 and the adJacent portion of the anode an annular recess or chamber.

The anode I is surrounded by the metal cylinder 33, which is placed with its edges on the annular disks 6. There is formed between the cylinder 33 and the middle portion of the anode I an annular chamber which serves for receiving the getter and which is connected with the chamber containing the discharge path by holes 4| in the anode I. The recessing of the anode I to form the said annular chambersincreases the flywheel effect of the resonator.

The external parts of the cartridge are con neoted together so as to be high-vacuum tight, there being provided in the way shown slits or pockets that serve for the reception of a jointing agent. As a jointing agent between the ceramic and the metal parts there is used glass flux, the glass of which has a coeflicient of expansion that corresponds to those of the parts that are to be connected together. The vacuum-tightfusion of the ceramic parts with the metal parts is effected by inserting, preferably by rubbing, the

.glass flux in pulverulent form or as a paste into the slits, and then subjecting the cartridge to the heat of a fusing furnace. The glass flux might be in the form of a pressure ring. On fusion the molten glass is drawn into the narrow gaps between the metal parts and the ceramic parts. In order to keep the high-frequency losses small, all conducting parts that conduct the high-frequency current are made of electrically highly conductive material (copper or silver) or provided with a coating of such material. The glass flux employed has a fusing point that is so low that it can unite the ceramic parts with the metal parts without the fusion of the metal parts. For this purpose a composition composed of lowfusing lead glass and of a corresponding ceramic material of like co-efiicient of expansion is suitable.

Since on the production of fusion there are necessary temperatures of 850-1000 C., which would be quite sufficient to cause decomposition of getter, the pellet 3 of getter is inserted after the jointing by fusion has been effected through an opening 3 in the getter chambe tion using flat electrodes.

which is subsequently sealed. The danger of the powdering of the insulating parts by the getter is prevented by the arrangement in question. The getter is arranged outside the chamber that contains the discharge path and in the chamber produced by the recessing of the anode.

The electrodes, including the grid and the anode, are adapted to allow of heat expansion without any stressing of the ceramic disks. The ceramic parts are arranged laterally of the electron path so that they cannot be impinged upon by scattered electrons and consequently no injurious wall charges can occur. The arrangement is also such that there can occur only the least possible metallic powdering of the insulating parts by material vaporised by the cathode.

Figures 1 and 3 illustrate the use according to the invention of a concentric-electrode system. Figures 2 and 4 illustrate a form of the inven- In this form a cartridge shown in detail in Figure 2 is inserted in the plates 4|! and 33 of a plate condenser, which are connected galvanically with pressed parts l2 and I3 of the cartridge and through them with electrodes (a grid and an anode) and form with the plates 40 and 33 walls of a frequency-determining resonating chamber.

The cartridge shown in Figures 2 and 4 comprises a hollow cylinder I! of ceramic material which carries with its lower edge the hot cathode l8 and the grid 36, and with its upper edge the anode, by means of the parts l2 and H, which are made of a fusible alloy (for example a suitable nickel-iron alloy) and have their external edges fused in the manner above stated with the edges of the ceramic cylinder IS. The anode is formed by the end surface of a hollow cylinder III, which is fastened to the part I! by fusion at several points. The ceramic cylinder II is perpendicular to the anode and consequently to the course of the ultra-short waves. The chamber bounded by the parts II and I3 serves forthe reception of the getter pellet IE; it is connected with the chamber of the discharge path by holes 38 in the hollow cylinder II. The getter pellet I5 is introduced, after the production of the high-vacuumtight seals in a manner similar to that hereinbefore described, through an opening which is provided in the part II and which is afterwards closed by a metal part l4, which is connected with the part l3 by welding. The leading-in wires 31 of the heating wire I! of the indirectly heated oxide cathode II are fused in the part i2 so as to be high-vacuumtight by means of glass-metal fusion. The grid 38 is formed by an end surface of a hollow cylindrical part II which is fastened to the part l2; the openings of the grid 36 are advantageously such as to allow of the passage of the electrons but to prevent the passage of the ultra-short waves so that the space containing the cathode and bounded by the grid is kept free from'ultrasshort waves. As a support for the oxide-covered cathode I 8 there is provided a body I, which consists of ceramic material and surrounds the heating helix I! of the cathode.

, The hollow resonator of the form shown in Figures 2 and 4 is a circular plate condenser made The described examples of the invention relate to three-electrode tubes and are preferably used in a breaking-field connection. Apparatus according to the invention may include diode systems or systems provided with more than one grid. Likewise arrangements according to the invention can be carried out for or in other connections, for example a reaction-coupling connection or a magnetron connection.

The construction of electron tubes according to the invention as cartridges is, as is the fusing method according to the invention, applicable generally to electron tubes, for example to electron tubes for the purpose of low-frequency amplification. The invention is particularly suitable for electron tubes that occupy little space and have electrodes at a very small distance apart (after the manner of acorn tubes or vessels) especially when it is a question of the production, amplification, or reception of ultrashort waves.

What we claim is:

1. Electron tube apparatus comprising a frequency determining hollow resonator comprising concentric outer and inner tubular conductors. means having an insulating wall at each end and defining a vacuum tight compartment located at a potential antinode in said resonator, and an electrode system in said vacuum tight compartment.

2. Electron tube apparatus comprising a frequency determining hollow resonator comprising concentric outer and inner tubular conductors, means having an insulating wall at each end and defining a vacuum tight compartment in said resonator, and an electrode system in said vacuum tight compartment, part of the interior of said compartment being free during operation from high frequency currents, and the cathode of the electrode system being located at said part of the interior of said compartment.

3. Electron tube apparatus comprising a frequency determining hollow resonator comprising concentric outer and inner tubular conductors.

meam defining a vacuum tight compartment in said resonator, and an electrode system in said vacuum tight compartment, part 01' the interior of said compartment being free during operation from electro-magnetic waves and a getter being disposed at said part of the interior of said compartment.

4. Electron tube apparatus comprising a frequency determining hollow resonator comprising concentric outer and inner tubular conductors, means including insulating end walls disposed in substantially parallel coaxially spaced relationship defining therebetween a vacuum tight compartment in said resonator, and an electrode system in said compartment having tubular electrodes disposed concentrically one within another coaxially of said insulating end walls.

5. An electron tube oscillator comprising a hollow member including a tube and end closures having conductive inner surfaces, a vacuum-tube in said hollow member having a conductive wail constituting a capacitance with said hollow member, electrodes in said vacuum tube for stimulating electromagnetic oscillations and separated from non-evacuated portions of the hollow member by at least one conductive wail of said vacuum tube, the conductive inner surface of the hollow member and the oscillation-stimulating electrodes enclosing a cavity closed oi! against loss radiation on all sides by metallic surfaces and serving as a frequency-determining resonator.

6. The electron tube oscillator of claim 5 having the electrodes disposed in a potential node of the resonator.

7. The electron tube oscillator of claim 5 having a grid between the anode and cathode and having a portion at the interior of the evacuated compartment tree from etic waves during operation and the grid located in this wave tree portion of said compartment.

8. The electron tube oscillator of claim 5 wherein the resonator is in the form of a concentric energy lead closed at both ends and having a length equivalent to a half wave length.

9.Theelectrontubeoscillatorofclaim wherein the wall of the space around the electrodes in which the frequency-determining electron flow operates is provided with an opening communicating with the hollow chamber of the resonator, said opening being the sole way therebetween and being small as compared with the dimensions of the rmonator.

ALFRED ALLERDING. WALTER DAILENBACH. 

